Trowbridge Lake
Trowbridge Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 13.5 ft visibility. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 3.5 µg/L. Maximum depth: 76 ft. Surface area: 620.81 acres.
- Clarity
- 13.5 ft
- Typical in August
- 74°F
- Max depth
- 76 ft
- Area
- 621 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 25
- Open water
- 220 days
Next lake in Otter Tail County
Trowbridge Lake is a 621-acre mesotrophic lake in Otter Tail County, Minnesota with a maximum depth of 76 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available. Compared to the 65 other monitored lakes in Otter Tail County, Trowbridge Lake ranks #25 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Good clarity, visible to about 13.5 ft. Phosphorus level: 16 µg/L. Chlorophyll-a: 3.5 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13.5 ft | Not graded |
| Phosphorus | 16 µg/L | Good |
| Chlorophyll-a (Algae) | 3.5 µg/L | Good |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Trowbridge Lake
Compare lakeside cabins, hotels, and vacation rentals near Trowbridge Lake in Otter Tail County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Water Temperature
Trowbridge Lake typically sits around 74°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 78°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 52 field readings (2011–2025) via the EPA Water Quality Portal. See the full Trowbridge Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Trowbridge Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was low (16,144 cells/mL) on November 8, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 76 ft |
| Surface Area | 621 acres |
| Shoreline Length | 8.8 mi |
| Littoral Zone | 44% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Trowbridge Lake
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-04-30 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 26.27 | 0.16 lb |
| Yellow Bass | 13.36 | 0.52 lb |
| Black Crappie | 5.47 | 0.39 lb |
| Largemouth Bass | 4.50 | 0.89 lb |
| Northern Pike | 4.33 | 1.44 lb |
| Hybrid Sunfish | 4.31 | 0.32 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Bluegill
Yellow Bass
Black Crappie
Largemouth Bass
From the 2025-04-30 survey
Leek (Trowbridge) Lake is a 609-acre mesotrophic (moderately fertile) lake located in north-central Otter Tail County approximately three miles northwest of Vergas, MN. Leek Lake is part of the Otter Tail River Watershed. Two small intermittent inlets are located along the southeast shoreline and one intermittent…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Trowbridge Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Leek (Trowbridge)Fisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Leek (Trowbridge) (1042)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Leek (Trowbridge)Fish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Leek (Trowbridge)Public Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.548 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.06 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.95 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (19 observations).
Estimated open water season: 220 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2017-04-05 (2017) | 2021-12-07 (2021) |
| Ice-In | 2018-11-13 (2018) | 2015-12-19 (2015) |
Most recent ice-out: 2025-04-14
EPA Impairment Status
Trowbridge Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0532-01 · Official waterbody report
County Ranking
Ranked #25 of 66 lakes in Otter Tail County
Nearby Lakes in Otter Tail County
Frequently asked questions about Trowbridge Lake
What is the water quality grade for Trowbridge Lake?
- Trowbridge Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 13.5 ft visibility. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 3.5 µg/L. Maximum depth: 76 ft. Surface area: 620.81 acres.
Is Trowbridge Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Trowbridge Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.5 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Trowbridge Lake?
- Trowbridge Lake typically sits around 74°F at the surface in August, from 52 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Trowbridge Lake?
- Trowbridge Lake has a maximum depth of 76 feet. The lake covers 620.81 acres.
What fish are in Trowbridge Lake?
- Fish species found in Trowbridge Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. Trowbridge Lake is located in Otter Tail County, Minnesota.
When does Trowbridge Lake thaw?
- Trowbridge Lake typically has ice-out around Apr 25. Ice typically forms around Dec 1. The open water season is approximately 220 days.
Does Trowbridge Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Trowbridge Lake (clouds, ice, or an off-season gap). The most recent reading was low (16,144 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
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Where this data comes from
100 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA100 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate